1. Field of the Invention
This invention relates to a precursor for an electrical storage battery comprising in a housing a plurality of positive plates, a plurality of negative plates dispersed therebetween and of separator plates inserted between adjacent positive and negative plates, all of the plates within the housing being in a perfectly dry condition wherefrom a practically unlimited shelf life of this article results. This article can be converted into an operative electrical storage lead battery by the mere introduction into the housing of a liquid sulphuric acid electrolyte.
It is an important feature of our invention that each separator is a densely compressed dry compact consisting substantially of a silica of the type which, when soaked with a sulphuric acid electrolyte, will undergo a drastic change of its consistency by conversion into a gel of a strength enabling it to properly act as a separator. This strength may be enhanced by fibres embedded in the gel. These gel separators are in intimate contact with the positive and negative plates of the finished operative battery.
2. Description of the Prior Art
U.S. Pat. No. 3,085,126 to Labino discloses a battery in which the separators inserted between the positive and negative plates consist of (a) 5 to 10% of coloidal silica or coloidal alumina and 85 to 95% of glass fibres. This mixture forms a porous body permeable to the electrolyte as distinguished from our novel separator forming a gel rather than a porous body. This gel has a strength and rigidity sufficient to hold the positive and negative plates in spaced relationship in which a shortcircuit between the plates cannot be formed. Moveover, this gel absorbs all of the liquid electrolyte this eliminating the risk that, if the battery should be accidentally turned upside down, it will lose liquid acid giving rise to corrosion and other trouble.
Operative electrical storage batteries of this kind are known per se, see U.S. Pat. No. 3,172,782 to Jache disclosing an operative storage battery in which the separators between the positive and negative plates contain a silica gel reinforced by embedded mats of glass fibre. These separators, however, are not formed by soaking a highly compressed compact of a silica-containing material with the liquid electrolyte. As distinguished from the precursor to which the present invention relates, the precursor of this prior battery is a housing containing the positive plates, the negative plates and the glass fibre mats therebetween. This precursor is converted into the operative storage battery by introducing a thixotropic gel liquified by agitation into the housing of the precursor. Liquifying this gel and filling it into the housing is a timeconsuming and difficult operation which is avoided by our invention which permits the liquid sulphuric acid electrolyte to be simply poured into the battery housing.